Transforming growth factor beta (TGF-beta), a multifunctional growth factor that for example controls proliferation or cellular differentiation, is one of the most important ligands involved in the regulation of cell behavior in ocular tissues in physiological or pathological processes of development or tissue repair, although various other growth factors are also involved. Increased activity of this ligand may induce unfavorable inflammatory responses and tissue fibrosis. In mammals, three isoforms of TGF-beta, that is beta1, beta2, and beta3, are known. In most cases, TGF-beta enhances extracellular matrix production and suppresses cell proliferation. Moreover, TGF-beta is capable of inducing a number of growth factors, that is connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF), fibroblast growth factors (FGFs), and vascular endothelial growth factor (VEGF), as well as TGF-beta1 itself. All these factors have important roles in restoration of normal tissue following injury.
The aqueous humor that bathes the inner ocular structures (corneal endothelium, iris, crystalline lens, trabecular meshwork, and retina) contains various cytokines and growth factors. TGF-beta, in particular TGF-beta2, is the predominant cytokine. Physiologically, TGF-beta is mainly produced in the ciliary epithelium and lens epithelium as a latent, inactive, form consisting of mature TGF-beta, the latency-associated peptide (LAP) (small latent form), and the latent-TGF-beta-binding protein (LTBP). Heterogeneous expression patterns of each TGF-beta isoform in the crystalline lens have been reported in humans and animals. During the clinical course of various ocular diseases, the concentration of TGF-beta2 in the aqueous humor changes. For example, in an eye with proliferative vitreoretinopathy (PVR), a disorder of post-retinal detachment and retinal fibrosis, the concentration of TGF-beta2 in the vitreous humor increases in association with the progression of retinal fibrosis. The concentration of total and active TGF-beta2 is also higher in patients with diabetic retinopathy and open-angle glaucoma than in normal subjects. In diabetic retinopathy, chronic obstruction of retinal microvessels induces upregulation of VEGF and chemotaxis of macrophages, a potent source of TGF-beta. VEGF and TGF-beta cooperate to induce both retinal neovascularization and fibrosis around these new vessels, which may potentially cause retinal detachment or bleeding. Increased TGF-beta2 levels induce matrix expression and deposition in trabecular meshwork cells, leading to obstruction of the aqueous drainage route and an increase of intraocular pressure in a glaucomatous eye. In each of these examples, TGF-beta plays a role in disease pathogenesis. In eyes with pseudoexforiation syndrome, a kind of glaucoma with deposition of exforiative material on the lens, iris, or trabecular meshwork, the level of TGF-beta1 increases, but the exact role of TGF-beta1 in the pathogenesis of this disease is unknown (see Shizuya Saika, Laborartory Investigation (2006), 86, 106-115).
TGF-beta is one of the most potent regulators of the production and deposition of extracellular matrix. It stimulates the production and affects the adhesive properties of the extracellular matrix by two major mechanisms. First, TGF-beta stimulates fibroblasts and other cells to produce extracellular-matrix proteins and cell-adhesion proteins, including collagen, fibronectin, and integrins. Second, TGF-beta decreases the production of enzymes that degrade the extracellular matrix, including collagenase, heparinase, and stromelysin, and increases the production of proteins that inhibit enzymes that degrade the extracellular matrix, including plasminogen-activator inhibitor type 1 and tissue inhibitor of metalloprotease. The net effect of these changes is to increase the production of extracellular-matrix proteins and either to increase or to decrease the adhesive properties of cells in a cell-specific manner (see Blobe G C et al., May 2000, “Role of transforming growth factor beta in human disease”, N. Engl. J. Med. 342 (18), 1350-1358).
Targeting TGF-beta has been proposed as a potential therapeutic measure for example in glaucoma. Concerning various aspects of TGF-beta in the pathogenesis of glaucoma, therapies should be directed to modulate its production, activation, interaction with receptors, downstream intracellular regulatory mechanisms and/or the final structural and ECM changes (see Prendes M A et al., Br J Ophthalmol (2013), 97, 680-686).
Glaucoma (GCM), based upon chronically increased intraocular pressure, is a progressive optic neuropathy characterized by progressive loss of retinal ganglion cells, which manifests clinically with loss of optic disc neuroretinal rim tissue, defects in the retinal nerve fiber layer, and deficits on functional visual field testing (see Danesh-Meyer et al., Ophthalmol. 2006, 113: 603-611). Glaucoma is the second leading cause for blindness in the adult in the USA. Despite a multitude of treatment options, including surgical procedures in referactory patients, blindness remains a major threat. Primary open-angle glaucoma (POAG) is the most common form of glaucoma in the USA. Worldwide, in the year 2000 the number of people with POAG has been estimated at nearly 66.8 million with 6.7 million having bilateral blindness (see Quingley, Br J Ophthalmol. 1996 May; 80(5):389-393).
Cataract surgery is the most common ophthalmic surgical procedure. Alone in the USA, up to 3,000,000 cataract surgeries are performed per year. The US government spends currently more than USD 3 billion per year on treating cataract (Medicare patients only). The lens of the eye is removed by the procedure, and an intraocular lens is implanted. The lens capsule remains in situ, and the posterior part of the capsule frequently develops posterior capsule opacification (PCO) due to mechanical disruption and potential other factors associated with lens replacement. This condition occurs in 20 to 40% of PCO patients, YAG-laser posterior capsulotomy (rates depend on country, lens type used and surgical experience) is performed within the first two years, to remove the opacification (see Johansson B et al., Br J Ophthalmol (2010), 94, 450-455; Mathew R G et al., Ophthalmic Surg Lasers Imaging (2010), 41, 651-655). The use of the YAG-laser is associated with distince risks, including retinal detachment (1-3%), cystoid macular oedema (up to 5%) and secondary glaucoma (see Billotte C and Berdeaux G, J Cataract Refract Surg (2004), 30(10), 2064-2071).
TGF-beta has been closely associated with the pathophysiology of both, GCM and PCO; so far, the effect of the TGF-beta protein has been inhibited by ALKS inhibitors as for example described in WO 2009/146408 or antibodies directed to TGF-beta, i.e., one of its isoforms, which are disclosed for example in WO 2012/167143. None of these compounds has so far been successful in effective inhibiting TGF-beta in the eye, and thus, to be successful in the prevention and/or treatment of ophthalmic diseases such as GCM or PCO.
It is the objective of the present invention to provide an oligonucleotide, preferably an antisense oligonucleotide, which is specifically inhibiting the expression of TGF-beta1, TGF-beta2, and/or TGF-beta3 mRNA, TGF-beta1 and TGF-beta2 mRNA, or TGF-beta1 and TGF-beta3 mRNA, or TGF-beta2 and TGF-beta3 mRNA, and consequently is highly efficient for use in prevention and/or treatment of an ophthalmic disease without causing any (severe) side effects.